> But having said that, there's an element of the social contract at play here. The exact same logic this guy is using suggests that he also shouldn't answer the questions of police investigating crimes in his neighborhood. "Have you seen this man? We think he just shot up your neighbor's car."

Quite importantly in this particular scenario, a police officer is not the same as a federal officer. Lying to a police officer is not a crime (at least usually, you may want to check your local statutes).